Scalability is the capacity to expand production as the need for additional power comes to the fore. A nuclear power plant can take years from the time of initial planning, permitting, and construction, whereas installation of solar panels for a home array will take only a couple of days. The material and labor costs during the construction or installation phase raise the cost of the power source over the cost to fuel and operate the facility once completed.
For necessarily large projects like nuclear or hydro-power facilities, long lead times are needed to bring power on line. This means that planning and construction must begin long before the power is available. This has considerable monetary cost because money is spent year after year before any money comes in from the sale of the power after completion.
An unpredictable risk inherent in the long term, big projects is that conditions may change. A steep drop in the economy during the recent “great recession” resulted in decreases in demand for energy world wide. Changes in technology, particularly with power sources which are more scalable may make a large project obsolete. Natural gas turbine technology is quite scalable. Turbines designed for jet aircraft can be used to generate electricity. The advent of directional drilling and fracking has greatly increased the availability and lowered the cost of natural gas which fuels scalable gas turbine facilities. Planning and construction of large scale coal plants are being canceled left and right.
Our economy is slowly recovering from the recession and new power sources are needed. Scalable power supplies are rapidly replacing large projects because they can reliably deliver power when and where it is needed and at a lower cost.
Solar power is booming across the country. Solar PV is growing 17 times as fast as the economy as a whole. This is due in large part to its scalability. If you need a little power, use just a few panels, such as what be need to charge the batteries on a remote cabin or an RV. To power the average home requires about 20 or 30 panels (10 kilowatt system which can produces 1100 kWh per month.)
For utility scale solar the numbers can get quite large. A one megawatt facility in Benton AR just went online. It employs 3,840 panels on a 5 acre site. The largest planned in Arkansas is an 81 MW, 500 acre facility with 350,000 panels. The country’s largest array not surprisingly is in California. At 550 MW, the array of over 2 million panels will power close to 100 million homes.
Wind is similarly scalable except at the lowest end of the spectrum. Modern wind turbines for utility scale facilities are 2 MW, however 8 MW turbines are being used in offshore locations. For perspective an average nuclear reactor is 1000 MW. Wind farms in the midwest vary in size but average around 200 turbines. A wind farm of this size could cover 50 square miles, but the actual footprint is minuscule as the land within the farm can still be used for forage/pasture.