Scaling current cereal production to a growing global population will be a challenge. Wheat supplies approximately one-fifth of the calories and protein for human diets. Vertical farming is a possible promising option for increasing future wheat production. Here we show that wheat grown on a single hectare of land in a 10-layer indoor vertical facility could produce from 700 ± 40 t/ha (measured) to a maximum of 1,940 ± 230 t/ha (estimated) of grain annually under optimized temperature, intensive artificial light, high CO2 levels, and a maximum attainable harvest index. Such yields would be 220 to 600 times the current world average annual wheat yield of 3.2 t/ha. Independent of climate, season, and region, indoor wheat farming could be environmentally superior, as less land area is needed along with reuse of most water, minimal use of pesticides and herbicides, and no nutrient losses. Although it is unlikely that indoor wheat farming will be economically competitive with current market prices in the near future, it could play an essential role in hedging against future climate or other unexpected disruptions to the food system. Nevertheless, maximum production potential remains to be confirmed experimentally, and further technological innovations are needed to reduce capital and energy costs in such facilities.

An earlier study by the same authors, entitled Building-Integrated Photovoltaics: A Case Study. completed in February 1995, evaluated the performance and economics of a series of roof-integrated photovoltaic systems in high-end commercial buildings. Results from that case study confirmed that infrastructure costs for PV systems are significantly reduced with building integration. The study found, however, that building-integration introduces a complex set of issues which greatly affect PV performance and viability. Figures 1-3 illustrate the primary advantages and disadvantages identified by the study for building-mounted and building-inte-Optimal BIPV Applications Kiss and Company Architects 9/29/95 Optimal BIPV Applications Kiss and Company Architects 9/29/95 Optimal BIPV Applications Kiss and Company Architects 9/29/95 Optimal BIPV Applications Kiss and Company Architects 9/29/95

Building water mass balances were performed for one 150‐story conventional building scenario for comparison with three scenarios of the 2020 Tower, a hypothetical 150‐story high‐rise building with on‐site wastewater treatment and reuse. To ensure that the assumptions for the hypothetical building are appropriate, a one‐year water balance was also conducted of the existing 27‐story Solaire building that partly closes the water/wastewater loop, meters major water flows and implements low‐flow/water conserving fixtures and appliances. For comparison, a conventional 27‐story building scenario with the same low‐flow/water conserving fixtures as the Solaire but no water reuse was also assessed. The mean daily indoor water use in the Solaire was 246 l/(d cap) which exceeds mean daily water use found in the literature. The water mass balances showed that an urban high‐rise building needs another source of water even when potable reuse water is produced because of losses during water end use and treatment (i.e., evaporation, water in treatment residues). Therefore, water conservation (i.e., modification of human behavior) and water efficiency improvements (i.e., equipment, appliances and fixtures) are important major factors in reducing the municipal water needed in all scenarios.

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A new version of the ENERGY-10 computer program simulates the performance of photovoltaic (PV) systems and evaluates a wide range of opportunities to improve energy efficiency in buildings. This paper describes two test cases in which the beta release of ENERGY-10 version 1.4 was used to evaluate energy efficiency and building-integrated photovoltaics (BIPV) for two federal building projects: an office and laboratory building at the Smithsonian Astrophysical Laboratory (SAO) in Hilo, Hawaii, and housing for visiting scientists at the Smithsonian Environmental Research Center in Edgewater, Maryland. The capabilities of the software, the design assistance provided by ENERGY-10, and a synopsis of results are given. Estimates of annual energy delivery by the five PV arrays of the SAO are compared to F-Chart to help inform a validation of ENERGY-10. Results indicate that, by simulating both the building electrical load and simultaneous PV performance for each hour of the year, ENERGY-10 facilitates a highly accurate, integrated analysis useful early in the design process. The simulation is especially useful in calculating the effect of PV on the building peak load, and associated demand cost savings.