Energy

Energy

A clean Energy Positive Community is possible, by designing for efficiency and producing clean energy onsite

As part of our design research on the Ford site, we assessed energy demand of the plan and the potential for on-site energy production, with the goal of accounting for all energy needs within the site. Reducing energy consumption will save natural resources, create more jobs, and reduce the impact of rising and increasingly volatile energy prices.

On-site Needs

The two main components of energy use on-site are building energy use and energy use in the industrial process.

Land-Use Type On-Site Needs kBTU/sq ft Area in sq ft Energy Needs kBTU
Housing 48/.8 2,179,776 106,373,068.8
Retail 64.1 623,544 39,969,170.4
Industry 47.3 1,008,062 47,681,332.6
Civic 43.7 557,201 24,349,683.7
Total N/A 4,368,583 218,373,255.5

*kBTU/1000 = 3412kWh

As energy use in the Highland Park area breaks down into 56% electricity and 44% natural gas, the total energy use results in 96,084,232.4 kBTU of heating and 35,840,862.5 kWh of electricity. This is under the assumption of no renewable energy on-site, as a base measurement; this allows for renewable energy use calculations below.

The second component of building energy use is that needed for the processes in the manufacturing sector. Energy use varies widely based on the sector in question, so estimation of actual energy use varies based on the ultimate manufacturer. We investigated a scenario where: 200MW of solar cells and modules would be manufactured and assembled on site and the remaining manufacturing space would be utilized by sectors with half the energy intensity of solar cell manufacturing. Using solar manufacturing in our calculations provides a high end estimate for the energy needs of the manufacturing sector on site, as it is among the highest energy intensity levels in manufacturing. This conservative estimate will decrease the probability of overestimating our capacity to meet energy needs on-site.

Energy demander On-Site Needs kBTU/sq ft Area in sq ft Energy needs kBTU
Solar panel production 1213.95 458,700 556,838,400
Other industrial processes 606.97 549,362 333,448,721.5
Building energy use total N/A N/A 24,349,683.7
TOTAL N/A N/A 1,108,660,377

 

Onsite Production Potential

Existing Hydroelectric
The Ford site currently has an 18MW hydroelectric dam on the Mississippi River. This hydroelectric facility was previously sold by Ford, but 5MW of its production was dedicated to the future site as a condition of its sale. This 5MW would produce 43,362,000kWh of electricity annually, assuming the over 99% conversion factor of hydroelectric generators. If all 18MW were able to be returned to the site, this would increase to 156,103,200 kWh of electricity annually.

Solar
Buildings in the ARISE design scenario, are intentionally oriented east-west to maximize solar exposure, with solar-accessible roof areas on all industrial, retail, and civic space, and half of the flat-roofing on residential space. Assuming 6 hours daily maximum solar exposure, solar panels on this area could produce 47,464,000 kWh of electricity. As solar production matches peak demand times of day, investing in solar energy may allow for future price contracts in the $0.15-0.40/kWh range, dramatically reducing payback periods.

Anaerobic Digestion
Anaerobic digesters process organic wastes to produce biogas (mostly methane) that can be used for heating or combined heat, power, and compost, which can be used as an input for urban agriculture. Accounting for the predicted food waste, paper waste, yard waste, and human waste produced in the ARISE design scenario, we estimated the potential on-site feedstock for an anaerobic digester and found that, in a combined heat and power application (assuming 75% electrical efficiency, similar to natural gas), such a digester could produce 49,744,000 kWh of electricity annually and 56,576,000 kBTU of additional heat annually.

Ground Source Heating
The Ford site has an extensive network (over 3 miles) of existing sand tunnels under the site, which have the potential to provide for the site’s heating needs. Furthermore, as existing geothermal applications tend to have 5-12 year paybacks, and the greatest costs of implementation are in digging trenches for pipes, ground source heating may be a substantial and highly cost-effective element of a site energy production strategy.

Wind Energy
Wind energy is still considered as an option for energy production, though initial estimates suggest that wind will not be the most scalable or cost-effective component.

Estimated Energy Production

On-site Energy Generator Energy Production (kWh) Energy Production (kWh)
Hydroelectric 43,362,000 (5MW) 156,103,200 (18MW)
Solar 47,464,000 47,464,000
Anaerobic Digestor 49,744,000 49,744,000
Total 140,570,000 253,311,200

Conclusion

These combined strategies (not counting ground source heating or wind energy) could meet 56,938,000 kBTU of heating load and 140,208,000 kWh (with 5MW from hydro) or 253,311,200 kWh of electricity (with all 18MW from hydro). Estimated site needs are 392,846,606.2 kBTU in heating and 252,460,709.5 kWh in electricity. Considering calculations of energy potential were conservative, and that neither additional potential energy sources nor additional efficiencies were considered in these calculations, the tradeoff between energy demand and energy production on-site could easily result in a net energy positive site.