New Rooftop Solar Thermal System Focuses on Space Heating and Cooling

Date: 9 Nov 2010 | posted in: Energy, Energy Self Reliant States | 0 Facebooktwitterredditmail

Solar thermal has generally been two distinct worlds, rooftop solar hot water systems and utility-scale concentrating solar power plants.

No more.

A new rooftop solar collector can provide thermal energy rather than producing hot water or electricity for space heating and cooling. With inexpensive fresnel reflectors to concentrate sunlight, the Chromasun could prove an interesting way to use distributed solar thermal energy for more than just hot water.

The unit produces temperatures up to 220 Celsius and promises to use less roofspace than comparable systems using solar PV. 

Now, what will it cost?

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Community Solar Power report – revised grades for project location

Date: 9 Nov 2010 | posted in: Energy, Energy Self Reliant States | 0 Facebooktwitterredditmail

The original edition of Community Solar Power received a lot of attention, for which we at the Institute for Local Self-Reliance are very grateful. The grading system we used for community solar projects was of particular interest, especially our offer … Read More

Hawaii Rolls Out Feed-in Tariff for Distributed Renewables

Date: 8 Nov 2010 | posted in: Energy, Energy Self Reliant States | 0 Facebooktwitterredditmail

The Hawaii Public Utility Commission moved ahead with the state’s feed-in tariff for projects under 500 kW, overruling objections from the state’s largest utility:

The decision came despite requests from Hawaiian Electric Company (HECO) to postpone the program over concerns that added distributed generation resources could destabilize the islands’ power grids.

…However, none of HECO’s objections “appeared to be fatal flaws that warranted any further delay in the development and implementation of the FIT [feed-in tariff] program,” according to statement released by the PUC.

The prices for the feed-in tariff program are as follows, with 20-year contracts:

 

Tier Technology Eligible System Size Rate
Tier 1 Photovoltaics Less than or equal to 20 kW $0.218/kWh
Tier 1 Concentrating Solar Power Less than or equal to 20 kW $0.269/kWh
Tier 1 On-Shore Wind Less than or equal to 20 kW $0.161/kWh
Tier 1 In-line Hydro Less than or equal to 20 kW $0.213/kWh
Tier 2 Photovoltaics Greater than 20 kW, less than or equal to 500 kW $0.189/kWh
Tier 2 Concentrating Solar Power Greater than 20 kW, less than or equal to 500 kW $0.254/kWh
Tier 2 On-Shore Wind Greater than 20 kW, less than or equal to 100 kW $0.138/kWh
Tier 2 In-line Hydro Greater than 20 kW, less than or equal to 100 kW $0.189/kWh
Baseline FIT Other RPS-Eligible Renewable Energy Technologies** Maximum size limits for facilities $0.138/kWh

The prices assume that the producer will take the Hawaii renewable energy income tax credit (35%). 

The program is capped at 80 MW of production: 60 MW on Oahu, 10 MW on the Big Island, and 10 MW for Maui, Lanai, Molokai combined.

Utility helps developers find capacity

The largest utility on the islands, HECO, has also published Locational Value Maps (LVM) to help developers identify places of greatest capacity on the existing grid.

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Cost of Fossil Fuels Makes Renewables a Harder Sell?

Date: 8 Nov 2010 | posted in: Energy, Energy Self Reliant States | 0 Facebooktwitterredditmail

This story on Sunday suggests that utilities are pulling back from investments in renewable energy over concerns about the cost

Invenergy…had a contract to sell [wind] power to a utility in Virginia, but state regulators rejected the deal, citing the recession and the lower prices of natural gas and other fossil fuels.

“The ratepayers of Virginia must be protected from costs for renewable energy that are unreasonably high,” the regulators said. Wind power would have increased the monthly bill of a typical residential customer by 0.2 percent.

Based on what price forecast?  The following chart illustrates the complexity of relying on fossil fuel prices when making decisions about renewable energy.  Note that wind and solar prices are relatively stable (i.e. zero).

The chart does a good job of showing the futility of predicting natural gas prices, but the timeline smooths out coal price changes, particularly by region.  Here’s a closer look at coal prices since 2007, courtesy of the federal EIA:

Utilities that are making shortsighted decisions about renewables based on current fossil fuel price trajectories are going to get burned, and so are their ratepayers. 

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Homes with Solar Sell Faster, and For More

Date: 29 Oct 2010 | posted in: Energy, Energy Self Reliant States | 0 Facebooktwitterredditmail

In by far the most exhaustive and detailed study to date, the National Renewable Energy Laboratory (NREL) found that solar homes sold 20% faster, for 17% more than the equivalent non-solar homes, across several subdivisions built by different California builders.

The study looked at a number of housing developments where the homes were otherwise identical except for the solar energy systems. 

Also interesting was that buyers were more interested in solar when it was-preinstalled:

If solar was already on the house, and factored into the price already, buyers were more likely to pick a house with solar. But if it was just one more decision to be made at the point of purchase, the decision got shelved.

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Hermann Scheer’s Feed-in Tariff Legacy: 75% of World’s Solar PV

Date: 27 Oct 2010 | posted in: Energy | 0 Facebooktwitterredditmail

The death of German renewable energy advocate Hermann Scheer last week – dubbed the sun king or even the Stalin of renewables – is a unique opportunity to reflect on his largest legacy, the feed-in tariff, a policy responsible for the rise of the renewable energy industry.

The feed-in tariff offers prospective renewable energy producers three simple and powerful tools: a guaranteed connection to the grid, a long-term contract for their electricity, and a price for their power sufficient to make a reasonable return on investment.  The result of the feed-in tariff is to make renewable energy generation easier to develop and easy to finance.  It creates a sort of energy democracy where, to paraphrase the chef from the Disney movie Ratatouille, “anyone can generate”.  

The feed-in tariff was the dominate policy in Denmark as wind power rose on the back of local cooperatives to provide as much as 20 percent of that country’s electricity.  Thanks to Dr. Scheer, it was the policy that energized Germany’s solar industry, one that now generates gigawatts of new distributed solar PV every year.  In fact, as the feed-in tariff policy spread to other nations, it has been responsible for the deployment of 75 percent of all solar PV projects and 45 percent of all wind projects worldwide.  

Though many policy makers are not familiar with the feed-in tariff, the policy has spread to North America, shepherding $9 billion of investment to Ontario’s renewable energy market as well as shaping the market in Vermont, California, and Gainesville, Florida.  

To learn more about the feed-in tariff, check out our 2009 report: Feed-in Tariffs in America: Driving the Economy with Renewable Energy Policy that Works or visit the Alliance for Renewable Energy or the FIT Coalition websites.

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Community Solar – Better on the Roof?

Date: 22 Oct 2010 | posted in: Energy, Energy Self Reliant States | 3 Facebooktwitterredditmail

When we released our report on community solar power last month, we expected a few comments on the grades we gave to the nine featured community solar projects. We also generated a really robust conversation about the location (on buildings or on the ground) of community solar PV projects and made a disheartening discovery about the cost of roof repairs when a solar PV array is present.

 

In the report, our criteria for solar PV location gave high marks for rooftop solar PV systems because of their use of existing infrastructure, lower marks for ground-mounted systems in brownfields, and the lowest grades for greenfield systems. In one particular case, we gave a ‘C’ grade to the Clean Energy Collective’s project because while it used otherwise unusable land near a sewage treatment plant, it was still ground-mounted.

The response to their ‘C’ grade made us re-evaluate our grading system. On reflection, there are three major considerations for the location of a community solar (or any distributed renewable energy) project.

Location Criteria for Community Solar

  1. Preservation of Open Space 
  2. Use of Existing Grid Infrastructure 
  3. Lifetime Cost for Participants 

 

Open Space

The open space issue cannot be ignored, as demonstrated by the opposition to centralized concentrating solar thermal power and solar PV power plants in the Mojave Desert and San Luis Valley in Colorado. Projects that use rooftops will rarely encounter resistance on environmental grounds (although there can be issues with historic districts). From the perspective of open space, there is still a higher value in a rooftop project than a ground-mounted one.

Existing Grid Infrastructure

The issue of existing grid infrastructure is not as clear cut. In general, distributed solar PV projects minimize the need for new grid infrastructure by plugging into the grid at low voltages and in a variety of places.

Rooftop solar would seem to have an advantage in this.  With few exceptions, a rooftop solar PV system can easily interconnect through the building’s grid connection. A rooftop solar PV system doesn’t change the capacity required by the local grid connection because net metering limits typically mean that no one installs a system that produces more than the building consumers.

But our error was to assume that ground-mounted systems would not take advantage of existing infrastructure, as well. In fact, the Clean Energy Collective solar project connects to existing infrastructure at an adjacent sewage treatment plant. Several other community solar projects in the report were constructed by utilities and presumably built next to existing substations where the new generation could easily be absorbed into the local grid. In other words, we should have graded this location criteria separately from the open space issue.

Lifetime Costs

The third issue – and one we’d never considered – is that rooftop PV systems may have to be removed and reinstalled if the roof needs replacement or repairs. While PV systems typically lose a small portion of their potential output (< 1%) each year, the systems can operate for decades, far longer than the typical residential or commercial roof (20-25 years in Minnesota). In other words, there’s likely to be one roof replacement during the life of a PV system.

Reinstalling a residential rooftop PV system could cost $6,250 or 25% of the installed cost of the system

In our investigation, we found that moving residential PV systems to accommodate a roof replacement could cost as much as 25% of the initial system cost (and over 35% of the net cost after the application of the 30% federal tax credit).  Moving systems on a commercial roof was less expensive, on the order of 15% of initial installed cost (around 25% of the system cost after the tax credit).   

The following chart illustrates the range of costs we found relative to an initial installed cost of $5.00 per Watt for commercial and residential PV systems.  

But this chart is somewhat disingenuous, because solar PV owners never pay the full installed cost.  Instead, there are a slew of tax credits and rebates that reduce this initial price.  The next chart shows these roof repair reinstallation costs relative to the net cost after the 30% federal tax credit.  

The cost issue is also complicated by various ownership arrangements. If the building owner also owns the array, the cost of moving the PV system is their responsibility. But what if they lease the solar array? Does the leasing company bear the cost of system safety when the roof is repaired or replaced or is it still the responsibility of the building owner? Will that cost be assessed when the roof is repaired or escrowed from the start of the project?

A CEC representative noted, “I guarantee you that a building owner (lessee) will never sign a long term lease that requires them to pay the costs of reinstalling a system after roof repairs, etc.” If CEC’s recently completed 77 kW community solar array had been built on a rooftop and required a move, the cost to its individual investors would likely be around $2,000, increasing the upfront cost for those individuals by nearly 30%. In addition, CEC couldn’t have offered the utility or its customers a 50-year service level agreement.

Conclusion: Location is Complicated

Obviously, there’s much more to the ground v. rooftop issue than meets the eye, from interconnections to roof repairs. Look for a transformation in our Community Solar Report in the next few weeks reflecting on this complex issue.

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Distributed solar less variable than centralized solar

Date: 21 Oct 2010 | posted in: Energy, Energy Self Reliant States | 0 Facebooktwitterredditmail

Traditionally, the reliability of small PV systems’ power output has been a concern for utilities, project developers and grid operators, since all it takes is a few clouds to disrupt the power flow of a small array. But the Berkeley Lab study suggests that when PV plant arrays are spread out over a geographic area, the variability in power output is largely eliminated.

This means that for utilities, the distributed generation of small PV arrays could mean increased efficiency, reduced costs and a quicker path to a cleaner energy portfolio.

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