50
Total Primary Energy consumption) has resulted in many studies of energy systems
looking just at the electricity sector, so the knock-on impacts of electricity on water
use, on other energy sources, and on the environment were often ignored. Similarly,
the dominance of petroleum as the primary input for transportation leads to designs
and models of transportation that ignored the availability of electricity, which is the
transportation fuel of the future. CO 2 and greenhouse gas emissions were not considered during the design of the modern energy system, and this has turned out to be
a serious problem.
As should be expected, water and food should be considered when developing
models of energy systems, and vice versa.
The water demands of energy are significant. Some uses, such a hydroelectric
generation, are largely non-consumptive, in that the water is returned after use
(except for the increased evaporation from the impoundment). Other uses, such as
thermo electric power plants (41% of all the water withdrawal in the USA in 2015),
irrigation (38%), and public water supplies (12%) are consumptive users of water
(USGS 2018). Although much of the water withdrawn for thermo electric power is
returned to the water body, significant evaporation occurs, and the returned water is
a higher temperature than the withdrawal. After 2007, a major shift in US electricity
generation away from coal to natural gas and renewables dramatically reduced
power plant water consumption. This has been offset somewhat by the increased use
of water in hydraulic fracturing for unconventional oil and gas production.
Conversely, the energy demands of water are also significant. Power is used to
pump water, move it, clean it for use, heat and cool it, and, to clean wastewater
before return to the environment. In a move toward recognizing the value of integrating water and energy systems, the considerable energy use to heat water has led
the State of California to prioritize the efficient use of heated water during a recent
drought because of its added benefits for energy efficiency. Some cities have created
hot water districts around thermo-electric plants, and some hydroponic and aquaponic facilities are co-locating with thermo-electric plants.
Similarly, energy use for food production is primarily a focus of food system
studies and is merely one more demand for energy use. However, significant energy
is used in agricultural operations and for creating inputs such as fertilizers and pesticides. Energy is required to preserve, move, process, and distribute food products,
as well as address waste by-products. Refrigeration to preserve foodstuffs is a significant part of energy use in the commercial and residential sectors.
Some key considerations for modern energy systems include:
• greenhouse gas emissions, treaties, and climate change (Chap. 11);
• rapid advancement in renewable energy technology and economics (solar,
wind, etc.);
• access to electricity and other modern forms of energy;
• aspirational development of renewable biofuels;
• the transition to electrical power from other energy sources;
• increasing use of geothermal energy for residential heating;
• rapid evolution and reliability problems of the massive and complex electrical
power grid (Chap. 10);
P. Saundry and B. L. Ruddell
Total Primary Energy consumption) has resulted in many studies of energy systems
looking just at the electricity sector, so the knock-on impacts of electricity on water
use, on other energy sources, and on the environment were often ignored. Similarly,
the dominance of petroleum as the primary input for transportation leads to designs
and models of transportation that ignored the availability of electricity, which is the
transportation fuel of the future. CO 2 and greenhouse gas emissions were not considered during the design of the modern energy system, and this has turned out to be
a serious problem.
As should be expected, water and food should be considered when developing
models of energy systems, and vice versa.
The water demands of energy are significant. Some uses, such a hydroelectric
generation, are largely non-consumptive, in that the water is returned after use
(except for the increased evaporation from the impoundment). Other uses, such as
thermo electric power plants (41% of all the water withdrawal in the USA in 2015),
irrigation (38%), and public water supplies (12%) are consumptive users of water
(USGS 2018). Although much of the water withdrawn for thermo electric power is
returned to the water body, significant evaporation occurs, and the returned water is
a higher temperature than the withdrawal. After 2007, a major shift in US electricity
generation away from coal to natural gas and renewables dramatically reduced
power plant water consumption. This has been offset somewhat by the increased use
of water in hydraulic fracturing for unconventional oil and gas production.
Conversely, the energy demands of water are also significant. Power is used to
pump water, move it, clean it for use, heat and cool it, and, to clean wastewater
before return to the environment. In a move toward recognizing the value of integrating water and energy systems, the considerable energy use to heat water has led
the State of California to prioritize the efficient use of heated water during a recent
drought because of its added benefits for energy efficiency. Some cities have created
hot water districts around thermo-electric plants, and some hydroponic and aquaponic facilities are co-locating with thermo-electric plants.
Similarly, energy use for food production is primarily a focus of food system
studies and is merely one more demand for energy use. However, significant energy
is used in agricultural operations and for creating inputs such as fertilizers and pesticides. Energy is required to preserve, move, process, and distribute food products,
as well as address waste by-products. Refrigeration to preserve foodstuffs is a significant part of energy use in the commercial and residential sectors.
Some key considerations for modern energy systems include:
• greenhouse gas emissions, treaties, and climate change (Chap. 11);
• rapid advancement in renewable energy technology and economics (solar,
wind, etc.);
• access to electricity and other modern forms of energy;
• aspirational development of renewable biofuels;
• the transition to electrical power from other energy sources;
• increasing use of geothermal energy for residential heating;
• rapid evolution and reliability problems of the massive and complex electrical
power grid (Chap. 10);
P. Saundry and B. L. Ruddell