The Energy Independence and Security Act of 2007

The Energy Independence and Security Act of 2007 (EISA 2007) endorses and increases the objectives set forth in the Energy Policy Act of 2005.

Although solar hot water systems are not considered a form of renewable energy, section 523 the EISA 2007 requires that at least 30% of the hot water needs for new federal buildings and major renovations must be accomplished by the use of solar hot water technology.

EISA 2007 also states that newly installed solar hot water systems must be life-cycle cost-effective. Solar hot water systems designed to supply from 70% to 80% of the load will reduce the life-cycle cost. Systems designed for 100% of the load will maximize the cost and will generally not be life-cycle cost effective.

Examples of federal facilities in compliance with EISA 2007 include the following:

One of the largest solar hot water systems in a federal building is located in the Phoenix Federal Correctional Institution. This solar hot water system provides 70% of the facilities needs by producing 50,000 gallons of hot water daily. The life-cycle cost effective system delivers   approximately 300 million Btu per month, offsetting 88,500 kWh per month which incurs a monthly average savings of $5600.

The solar hot water system at the Mid-Atlantic Social Security Center in Philadelphia supplies 124, 000 Btu in order to produce 1100 gallons of hot water per day, about 70% of the total load. In addition to offsetting substantial KWh’s, the yearly cost savings is approximately $5,000 per year and is life-cycle cost effective.

Future design and construction of solar hot water systems in federal buildings continues to be imminent. Currently, only 1% of the 500,000 federal buildings owned and occupied by the U.S. government use solar hot water systems. There seems to be no shortage of federal buildings that could be replaced or updated to include solar hot water systems.

The efficiency of solar collectors is dependent on several features in a solar hot water system. In addition to the amount of solar radiation absorbed by the solar collector and the temperature of the ambient air, the efficiency is also determined by the flow rates of the heat transfer fluid in the solar hot water system.

At it’s most basic level any solar collector is nothing more than an air to liquid heat exchanger.  The sun provides the heating on the outside of the collector (air side) and the fluid flowing through the collector picks up the heat as it passes through.  In any air to water heat exchanger the amount of heat that is transferred over time increases as the flow rate increases. Along the same lines, any heat exchanger that the solar fluid passes through (either in a tank or external) increases it’s rate of heat transfer with higher flow as well.  So, higher flow rates increase both the amount of heat that is extracted from the collectors as well as the amount of heat that is passed into storage.  In general, the efficiency of solar water heating systems improve as flow rates increase. The reason all systems aren’t pumped at the maximum flow rate is because as the flow rate increases the pumping power required generally increases as well.  At a certain point the increased efficiency you achieve through higher flow rates is offset by the greater pumping power.

While we get the question all the time “what is the right flow rate for this collector?”  The real answer is hidden in the details.  We do not like to see systems that are pumped at a fluid velocity beyond what the piping can support (see previous blog).  That being said adding a flow meter to a system so you can make sure it matches exactly the “recommended” flow is counter productive.  Flow meters to confirm flow make sense.  Flow meters to control flow don’t.  Pumps come in a finite number of sizes and the best answer is to choose a pump that matches your system design.  When in doubt choose a larger pump (but not beyond the flow limits of the pipe) and the little you pay extra in pump energy will more than be made up in system output.

Everyone that has looked into the details is impressed with the relative economic value of a solar water heating system compared with any other renewable energy source. Even if a potential customer is impressed with the economics of solar heating it doesn’t mean that they can necessarily pay for it. Many potential customers don’t have access to the cash so discussions of tax incentives and rebates fall on deaf ears if they don’t have the money up front.

One of the missing pieces in the solar heating equation has been the financing. This has been a hurdle at both the residential and commercial level. I am aware of a number of banks that offer different systems but one that came to mind recently that I thought had some merit was www.sameascashloans.com . The premise is that you can offer your customers a solar system and they can defer the first payment for anywhere between 3, 6, 12, or 18 months. This way the customer doesn’t have to be cash out of pocket until they are realizing the tax savings.

On the commercial side it is a little more like standard financing but the availability of financing makes this a strong option for growing your solar heating business.

With the cost of conventional energy ever increasing, consumers are becoming more interested in the use of solar energy. But which solar energy technology makes the most sense for the average consumer, solar heating or solar electric?

A solar heating system generally consists of solar collectors, a water storage tank, a pump and automatic controls. The estimated cost of a hot water solar heating system for a typical single family home is between $4,000 and $8,000, including installation. The system will replace approximately 80% of the energy used by a conventional hot water system, and represents a cost savings of $500 to $600 a year. The payback will average between 5 to 7 years after tax credits, meaning that after 5 to 7 years the total cost savings will have paid for the initial cash investment.

The components of a solar electric system are the photovoltaic solar collectors, an inverter, a charge controller and batteries. The projected cost of a grid-tied solar electric system for the same typical single family home is from $25,000 to $35,000 and will supply approximately 20-25% of the electricity usage of the home. The yearly savings would be between $500 and $600. The payback of the system is estimated at 15 to 25 years.

The initial costs of both of the solar hot water heating system and the solar electric system may be reduced by federal tax credits and state tax incentives. The cost savings per year and payback time for both systems will vary depending on the exact costs of the system components, actual current energy costs and future increases in energy costs.

Neither system is 100% efficient, since energy is lost due to conversion processes. Solar hot water heating systems are considered to be between 35% and 50% efficient, compared to solar electric systems which are 4% to 13% efficient.

In our opinion, because of the lesser initial expenditure, the quicker return of the investment and the higher rate of efficiency, the solar hot water heating system is the better, more cost effective choice.

The European Member States have to work out a Renewables Action Plan this year, outlining how it will reach its 2020 target
by Werner Weiss and Peter Biermayr
London, UK [RenewableEnergyWorld.com]

The European Union and its Member States have committed themselves to achieving a 20% share of renewable energy in Europe’s final energy consumption by 2020. As only three renewable sources (biomass, geothermal and solar) generate heat, it is crucial to clarify how these different sectors can contribute to the renewable energy target. A new study being released this autumn – Study of the Potential of Solar Thermal in Europe, which has come from two Austrian bodies (AEE – Institute for Sustainable Technologies and Vienna University of Technology) examines the growth that can come from solar.

Obviously, solar thermal systems will be needed to provide a substantial share of the low temperature heat: deep geothermal sources are limited to a few locations in Europe, and shallow geothermal is considered within this study as an energy efficiency technology; biomass will be used for transport fuels, electricity generation and medium-to-high temperature applications.

In order to provide the European Union and its Member States with substantiated information on the solar thermal contribution to the 20% renewable energy target and its long-term potential, detailed surveys were conducted using a representative sample of five European countries – Austria, Denmark Germany, Poland and Spain. The information gathered was then extrapolated to cover the 27 EU countries. The study examined both the technical and economic potential of solar thermal technologies, for different applications, including low-temperature industrial heat requirements and cooling.

In order to determine the potential contribution solar thermal could make to the overall heat demand in the selected reference countries, a model was developed for the future demand – taking into account energy efficiency measures. Using this model as a base, future heating and cooling demand was calculated for 2020, for 2030 and 2050. The model includes three scenarios and focuses on the following segments:
* space heating of residential buildings
* hot water preparation in the residential sector
* space heating in the service sector
* industrial low temperature heat (up to 250°C)
* air conditioning and cooling in the residential and service sectors

The three scenarios are a ‘Business As Usual scenario’ (BAU); an ‘Advanced Market Deployment scenario’ (AMD), which includes financial and political support mechanisms such as subsidies and obligations, moderate energy efficiency measures and improved research activities; and a ‘Full R&D and Policy scenario’ (RDP), which includes substantial financial and political support mechanisms, energy efficiency measures and research activities.

Contribution of Solar Thermal to the EU 20% Renewable Energy target

Assuming there is a 9% reduction of the overall final energy demand due to energy efficiency measures by 2020 (compared with 2006), then solar thermal would make up 6.3% of the European Union’s 20% renewable energy target under the RDP scenario, and 2.4% under the less ambitious AMD scenario. The share of renewables in 2005 (to the EU-27’s total energy consumption of 13,609 TWh) was 8.5%. To reach 20%, an increase of 11.5 percentage points in renewable energies is required across the EU-27 countries by 2020. The contribution of solar thermal to that increase would be 12% according to the RDP scenario, 4.5% according to the AMD scenario and 2.9% in the BAU scenario.

To reach the goals of the RDP scenario, a 26% average annual growth rate of the European solar thermal market is needed up to 2020. (By comparison, the average annual market growth in Europe between 2000 and 2007 was 12.4%.) A 15% average annual growth rate is required to reach the goals of the AMD scenario and a 7% growth rate for the BAU scenario. The resulting total collector area by 2020 would be between 97 million m2 (BAU) and 388 million m2 (RDP). These collector areas correspond to total installed capacities of 67.9 GWth and 271.6 GWth, respectively.

Economic Effects

According to the RDP scenario the effect on employment would be considerable. In total, the solar thermal sector would encompass 470,000 full-time jobs in 2020, in the European Union domestic market alone. €214 billion would be required in the solar thermal sector to reach the 2020 goals of the RDP scenario. This includes production, engineering, trade and installation of solar thermal systems from 2006 to 2020.

Solar thermal contribution to the energy supply and CO2 reduction

The solar yield in the RDP scenario is 155 TWh in 2020. This corresponds to an oil equivalent of 22 billion metric tons. Taking this oil equivalent into account the annual contribution to the CO2 reduction by solar thermal systems is 69 million metric tons.

Technology Innovation

Stepping up solar on this scale will require innovation. In order to use the potential much larger roof and facade areas will be needed for the installation of solar collectors.

Large-scale solar renovation of buildings will make use of prefabricated elements, with solar providing space heating, cooling and hot water. Combisystems will play an essential part, and a key issue is the development of thermal energy storage.

Long-Term Potential – Beyond Domestic Hot Water

In 2050, the solar thermal contribution to the European Union’s (EU-27) low temperature heat demand ranges from 47% (RDP scenario) to 8% (BAU scenario).
The corresponding annual solar yields are 1552 TWh (RDP) and 391 TWh (BAU). The collector area needed to reach these goals is between 8 m2 (RDP) and 2 m2 (BAU) per inhabitant in the EU-27. The resulting total collector area is between 3.88 billion m2 (RDP) and 970 million m2 (BAU).

If solar thermal is to contribute significantly to the long-term heating and cooling demand in EU-27 countries then the primary focus in central and northern Europe must be on systems for space heating (solar combisystems) and in the Mediterranean area on systems providing space heating, hot water and air conditioning (solar combi+ systems).

If the focus remains solely on solar thermal systems for domestic hot water preparation, then the solar thermal contribution to the long-term final energy demand will be limited. By 2030 the full potential for these applications will have been reached and the market would be reduced mainly to the replacement of old systems. Another important segment with considerable potential is low-temperature process heat for industry, (up to 250°C).

With upscaled R&D and market/political support, solar heat can make a valuable contribution to Europe’s energy future. It’s the right moment – in fact, without the renewable heat sector, the 2020 targets will not be reached.

Werner Weiss is at AEE – Institute for Sustainable Technologies, Gleisdorf, Austria. Peter Biermayr is with Vienna University of Technology Energy Economics Group, Austria.

The full version of the Solar Thermal Potential in Europe study is available: http://www.estif.org/.

This study was prepared in the framework of the EU-funded project RESTMAC, TREN/05/FP6EN/S07.58365/020185. The Solar Thermal partner in the RESTMAC project is ESTIF, European Solar Thermal Industry Federation.

Solar heating system gets prominent display during the 2009 solar tour.

http://wake.mync.com/site/Wake/news/story/42654/solar-powered-homes-businesses-go-on-display/

When a customer has a solar heating system installed in their home they expect (and rightfully so) that their energy bill will drop pretty significantly. When a customer doesn’t see as much of a drop as they expect the question is why. One of the things that I encourage solar contractors to do is calibrate the expectations of their customers. Let them know what they should expect from their system. The best way to do that is to provide a simulation report . With this tool they can easily see what to expect from the system. Things keeps everybody on the same page about what the system should be producing.

Thanks for checking out the SOLARHOT blog. This blog is a place where we share tips, ideas, and interesting information from across the solar heating industry that we believe would be helpful for solar installers or general solar enthusiasts. The tips and ideas come from our interaction with people in the trades, end customers, and general industry info. SOLARHOT designs manufactures and wholesales solar water heating systems so this blog will relate primarily to solar water heating but we also have information about other technologies in the renewable and conventional energy space.