Trendspotting: US States Warming up to Renewable Energy Heating and Cooling, Part 1

Of the fifty U.S. states, four territories and one District of Colombia, almost forty of them have some kind of renewable energy requirement on the books and of those forty, only about fourteen allow some type of thermal renewable energy to meet at least a portion of its renewable portfolio standard. But that might be changing.

A quiet trend is emerging with two states leading the way.  In recent months, both Maryland and New Hampshire have tipped the scales in favor of thermal renewables by passing or amending innovative, groundbreaking laws that will significantly drive up the use of thermal renewable energy in their states and beyond.

A Brief Look at the Technologies Involved

Renewable heating (and cooling) technology depends on the sun, the earth and sustainably harvested forests to fuel its systems.  The sun provides heat for hot water in solar water heating (SWH) systems, which work through solar panels placed on a roof.  The panels are filled with a glycol solution that circulates throughout the home or business to heat water, usually in a tank, providing heat and/or hot water for the facility.  The system is generally closed loop so that once cooled, the solution returns to the roof to be reheated by the sun. SWH systems replace electric, gas, or oil-fired water-heaters and can also be used for space heating.

Geothermal heating and cooling systems, also known as ground-source heating and cooling systems, ground source heat pumps, geothermal heat pumps or geothermal exchange systems, use a heat pump to circulate a water solution throughout a home or small commercial facility.  The system begins with pipes laid out either horizontally or vertically in the ground, through which a fluid flows, taking on the temperature of the ground.  At depths of about 6-8 feet underground, the temperature is a fairly constant 40 degrees to 50 degrees F, which means that a heat exchanger has little work to do in order to raise that temp to 71 degrees to heat a building in the winter.  In the summer, those same temps work for cooling. Geothermal heat pumps offset heating and cooling loads generally powered by gas, oil, or electricity.

Biomass thermal energy refers to biomass space and domestic water heating, process heat, and the thermal portion of combined heat and power and often uses wood pellets as the fuel source. Pellets are manufactured from waste wood, forest residues, and other sustainably harvested wood.   

Growing Recognition of the Importance of Renewable Heat

In many areas of the U.S., particularly in the Northeast and Mid-Atlantic regions, homes are heated with oil. ‘New Hampshire alone exports almost one billion dollars annually of wealth for heating oil and propane alone,’ said Charlie Niebling, General Manager at New England Wood Pellets (NEWP). Niebling is part of the Biomass Thermal Energy Coalition (BTEC), which was instrumental in changing N.H. law.  The state will now require that thermal energy be used to meet its RPS making it the first state in the country with a thermal energy carve-out on the books. ‘It makes sense because a third of the energy we consume in this country is heat and yet it’s been almost entirely overlooked,’ said Niebling.

But there are reasons that heat hasn’t been recognised for state renewable portfolio standards up until now and they are good ones. ‘Trying to extend the RPS concept to heat is complicated,’ said Niebling.  ‘Heat is for the most part, unregulated, completely decentralised – you have thousands of companies delivering the energy not tens or even fewer than ten as is the case in N.H.,’ he explained.  What’s more, heat is also more difficult to measure, many believe.  ‘Solar hot water has been available in N.H. since the RPS was created,’ said Heather Manypenny, Power Resources Executive with the New Hampshire Electric Cooperative. ‘To my knowledge no one has actually managed to get a REC from solar hot water,’ she said.

Since utilities sell electricity, adding heat to a renewable portfolio standard and asking the utility to regulate it, doesn’t seem like a match made in heaven.  Rick LaBrecque of Public Service New Hampshire (PSNH) the state’s largest utility, called the new law ‘odd’ in that the electric utility will be regulating something that is non-electric.  He added however that the new regulation will not be a significant administrative burden on the utility and therefore it is seen as generally all right.  ‘We feel that is was a good package that addressed a lot of things, corrected some things that needed to be addressed and, you know, we’re fine with it,’ he said.

On the other hand, many industry analysts argue that thermal energy is a much more cost-effective way to generate renewable energy credits (RECs), the credits that utilities must procure to prove that they have met their RPS’s. For example, when comparing solar PV output to solar thermal output, thermal wins every time.

‘It’s pretty clear the conversion of solar energy into thermal output is a significantly more efficient process than the conversion into electrical output,’ said Ron Gehl, who is Chair of the Solar Thermal Technical Division of ASES and President of EOS Research. ‘Quite typically, depending on system design and all that, but quite typically [it is] four to five times more efficient as typical PV output.’

Renewable technologies that can claim the attributes ‘less expensive’ and ‘more efficient’ are the Holy Grail for renewable energy and utilities ought to start taking notice, said Chris Williams, a consultant and Chief Marketing Officer at Heatspring Learning Institute. ‘I feel like the utility would want to do it [incorporate thermal energy into an RPS] for the simple reason that if you look at raw installation costs verses energy production per year, it’s a cheaper way for them to get to the RPS. No question.’

But how should states move forward with policy? Check back tomorrow for Part 2, which will discuss metering, monitoring, and states that are leading the way in thermal energy.

Lead image: Solar panels via Shutterstock

Part 1 of this article can be found at this link.


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Jennifer Runyon has been studying and reporting about the world's transition to clean energy since 2007. As editor of the world's largest renewable energy publication, Renewable Energy World, she observed, interviewed experts about, and reported on major clean energy milestones including Germany's explosive growth of solar PV, the formation and development of the U.S. onshore wind industry, the U.K. offshore wind boom, China's solar manufacturing dominance, the rise of energy storage, the changing landscape for utilities and grid operators and much, much, more. Today, in addition to managing content on POWERGRID International, she also serves as the conference advisory committee chair for DISTRIBUTECH, a globally recognized conference for the transmission and distribution industry. You can reach her at

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