What do a hospital, an army base and a Walmart store have in common? The answer is that they all improve their energy efficiency and increasingly produce their electric power on site, behind the (utility) meter. Each single site may not represent a big electric load, but it starts to add up. In fact it may be part of the reason why electric utilities are facing lower load growth and in some cases even negative load growth.
The electric load growth, which ultimately drives the need for net additions of power generation, was 2000 – 2008 about 1.2 % year. After the recession it has been flat to 1.0 %. In EIA’s (U.S. Energy Information Administration Administration) Short-Term Energy Outlook forecast U.S. electricity consumption to be by and large flat in 2014 and have a very small growth in 2015.
The low load growth has been explained by/blamed on weak economy as well as “structural changes”. However, at 2 % GDP growth one would certainly expect growth in electric demand. Thanks to access to inexpensive natural gas chemical and primary metals industries are now expected to grow. In terms of structural changes the “internet economy” rather increases the electric demand.
Nevertheless, the load growth seems lower than what traditional economical models have projected. Energy efficiency is definitely a factor. For example appliances and lighting efficiency continue to improve. LED lights, which use about 75 % less energy than traditional light bulbs, represent a “step-function” change. Add to that more energy efficient buildings, stimulated by programs like LEED (Leadership in Energy and Environmental Design).
Another factor is distributed generation, still small but starting to be more significant. With distributed generation load is served on site, behind the meter. The total gross load may in fact be growing but the portion supplied on site is a reduction from what otherwise had been served by the electric utility. One may call it the “invisible load growth”. Indications of case made:
Gundersen Health System’s energy plan may be unique in its ambition and reach, but serves as a good illustration for changing times ahead in the healthcare industry. Their plan Envision (www.gundersenenvision.org/), which was launched in May 2008, targets to be 100 % “energy independent” in 2014. The plan incorporates energy efficiency, on-site and off-site renewable energy. For on-site energy they use biomass boilers (wood-waste) and biogas generator (conditioned gas from a nearby landfill) as well as geothermal heat pumps.
Driven by high targets for resilience the Army and the Navy have taken a lead in developing micro grids. In order to stay mission ready regardless what the micro grids incorporate existing back-up generators, new CHP (Combined Heat and Power), solar arrays and energy storage/battery systems.
Walmart has become the second largest on-site green power generator in the US deploying rooftop solar, biodiesel generator sets, fuel cells and also micro-wind. About 75 % of the Walmart-owned locations in California have now rooftop solar.
Looking forward these trends are likely to continue. Rooftop solar installations keep growing. For example it took California 30 years to reach 1000 MW of rooftop solar. In 2013 it doubled. It corresponds close to 3 % of all installed power generation capacity in California! The rapid growth has been enabled by substantial subsidies, but also thanks to global economy of scale driving down costs. Worldwide 50 GW of capacity of solar photovoltaic (PV) was installed by 2011. By the end 2012 it had surpassed 100 GW! By the end of 2015 it may have doubled again, i e reaching 200 GW.
In the US access to inexpensive natural gas from the shale gas development is also very favorable for on-site generation, especially in CHP applications, with micro turbines, fuel cells as well as natural gas fired reciprocating engines. For the latter ones natural gas makes it much easier to meet air quality requirements, which have been a major limitation for back-up diesel generators. Some experts predict that among DER (Distributed Energy Resources) CHP and back-up generation may even grow more than solar PV and distributed storage.
Long-term (2025 and beyond) the joker in the deck of cards for load growth is plug-in electric cars and how they will be charged. If the penetration of plug-in electric cars will be high it may ultimately result in a load growth never seen since the introduction of air condition.